Deals Of The Week - hours only!Up to 80% off on all courses and bundles.-Close

Wrap course as a gift

Prepare your gift and double-check it looks just right.

Form validation errors

Recipient's Name:
Recipient's Email:
Your Message (Optional):
Proceed to Checkout

Window Functions in PostgreSQL

When window functions are evaluated
Window functions and GROUP BY
Summary

Instruction

Good. As you can see, the query failed. However, let's take a look at another modification of this example:

SELECT
  category_id,
  MAX(final_price) AS max_final, 
  AVG(MAX(final_price)) OVER()
FROM auction
GROUP BY category_id;

What will happen now?

Exercise

Run the template.

As you can see, the query now succeeded because we used an aggregate function (MAX(final_price)) that was indeed available after grouping the rows. By the way, this is the only place where you can nest aggregate functions inside one another.